Piston for gasoline meters and the like



April 7, l`931.'

l a-H. THQMPsoN 1,799,875

IISTOHy GASOLNE METERS AND THE' LIKE Filed Dec. :5, 192s Patented Apr.V 7, 1931 PATENT lOFFICE ERNEST H. THOMPSON, F EVANSTON, ILLINOIS PISTON FOR Gr'.ASOII'JIISI'IEI METERS THE LIKE Application led December 3, 1928. Serial No. 323,543.

This` invention relates to certain improvements in pistons and particularly to a ,substantially free or floating piston designed especially for use in connection with gasoline metering devices.

In the type of apparatus above referred to, the piston is freely supported within a cylinder and is acted on by the gasoline iiowing through the cylinder, certain valve mechanism being associated with the cylinder to periodically admit and permit the discharge of the liquid, to and from the cylinder, said admission and discharge preferably taking place at opposite ends of the cylinder. 1.5 The general arrangement of the device as briefly outlined above is shown in applicants copending application led March 5, 1928, Serial No. 259,207, and the present invention relates to an improved form or construction of piston as distinguished from that shown and described in said application.

The object of the present invention is the production of 'a piston of the floating type which will be capable of performing` its desired functions in a continuous manner and in direct contact' with the gasoline or similar fluid, under extreme temperature fluctuations or changes without failure or loss of efficiency under continuous service.

In app'licantsl device, in connection with which the piston is used, the piston is caused to reciprocate within the cylinder by the gasoline or similar liquid flowing through said cylinder and is in direct contact with the liquid, and owing to the peculiar characteristics of gasoline, under actual working conditions, considerable trouble and diiiiculty has been experienced in maintaining the device in constant and uninterrupted operation under all conditions incidentl to the practical use thereof. ff

In these devices it is of course important that there be as small a clearance as possible between the cylinder walls and the piston to prevent leakage, yet this clearance cannot be so small as to causeexcessivefriction and Y put any3 appreciable load on the liquid being measured, in reciprocating said piston. It.

is also desirable that the piston be substantially the same specific gravity as the gasoline or liquid being measured.

Numerous forms of pistons have been devised and used by applicant, but in every instance, owingto certain defects, a continuous successful working of the device was not accomplished until the development and discovery and use, of the present construction of piston as disclosed in the instant linvention.

These metering devices, to be accurate must be capable of operation underv very slight pressures or with very little effort. In other Words, the liquid being measured should be required to do only the minimum amount of work. There arev various other features incident to this metering device `tending towards the production of this result, which other features however form the subject matter of separate applications and are also shown in a less perfected form, in the application hereinbefore referred to, already iled.

One of the most important improvements however, and as a matter of fact the most vital one, is in the piston as produced in accordance with the present invention.

It will, of course, be obvious that no lubricant can be used to reduce the friction between the piston and cylinder where the piston is in direct contact with raw` gasoline, gasoline being a solvent for grease, and oil, andlfor that reason piston rings are not practica Applicant has tried substantially!d all metals and metal alloys, some of which being known as self-lubricatin metals or alloys, but in every instance, ow1n to the penetrating characteristics of gaso ine, after a short period of use these metal pistons would become "devoid of lubricating qualities and trouble would develop owingto the sticking of the piston in the cylinder.

Various compositions for the piston-were used such as graphite or the like only to-fail for the same reason.

A solid cork piston was then used but after a certain period of use these cork ,pistons would swell and stick in the cylinder, it of course .to be understood that it would only require a very slight degree of swelling to cause the piston to stick as only a very small clearance could be allowed between the piston and the cylinder.

Solid composition cork pistons were also tried but contrary to the natural cork, this composition cork would shrink permitting the escape of gasoline past the piston and reultirg in an inaccurate registering ,of the 1qu1 Aside from the liquid characteristics of the gasoline there was another factor to contend with, to wit, heat, very noticeable during hot weather, this warming up or heating of the gasoline only increasing the shrinking or swellin of the piston as the case might be accor ing to the particular characteristics of the material from which the piston was constructed.

It -was not until the construction as disclosed in the present application was devised, that the chief diiiicult-y was overcome and a perfected device produced, capable of continuous and uninterrupted operation under the most rigid test. These metering devices using the form of piston set forth in the instant application, have been successfully operated in temperatures ranging from zero to above the boiling point, without interruption or appreciable variance in accuracy.

, rBriefly stated the improved piston comprises a hollow cylinder, closed at each end by a circular plate or disk, the diameter ofv the cylinder being slightly less than that of the disks or plates, and around the outer circumference of the cylinder isvsecured a relatively thin sheetof composition cork. `IlVith this construction all of the advantages of a cork piston are obtained, yet there is not enough metal or cork in this construction to be efected by either the tem erature or liquid suiciently to be noticea le even in the sli htest degree.

nstead of applying a single continuous sheet or layer of cork to thehollow cylindrical piston, this cork layer may be formed of two separate ring sections 1n conjunction with outer rings of chamois or the like, for the purpose tobe hereinafter more fully described.

\ The preferre embodiment ofthe invention is illustrate` inthe accompanying drawing, in which Fig. 1 is a view partly in section and partly in elevation showmg-the improved piston in operative position;

Fig. 2 is a perspective view of the piston;

Fig. 3 is a horizontal sectional view;

Fig. 4 is a vertical sectional view; and

Figs. 5 and 6 are enlarged detail views of modifications.

Referring to the drawing in detai1,the novel piston comprises a cylinder portion 1 provided with head sections 2 and 3, said parts being secured together by a tie bolt or pin 4.

The cylinder 1 and head sections 2 and 3 are formed of relatively thin metal and these parts may be constructed and assembled in any preferred manner, the arrangement herein shown and described being only one of many ways in which these portions of the piston may be constructed. It is also to be noted, that although the piston as illustrated, is cylindrical, the invention is equally applicable to a cubic or spherical piston.

In the preferred design as shown, the head sections 2 and 3 are of slightly larger diameter than the outside diameterof the cylinder 1, forming circumferential iianges or the like 5 and 6.

Applied around the outside of the cylindrical portion 1, between the ,anges 5 and 6, is a relatively thin layer or sheet of cork or similar composition 7, said cork bein secured to the cylinder with any preferre adsolvent properties of gasoline and like fluids.

This layer or sheet of cork is of slightly less Width than the distance between the flanges 5 and 6 to allow for any slight expansionvof the cork under working conditions.

These flanges 5 and 6 are for the purpose of protecting the edges of the cork layer 7 but they do not extend out to or beyond the outer face of said cork layer so that the corls` is the only portion of the piston that actually engages the cylinder walls, in connection with which the piston is used.

In Fig. 6 a modified construction is shown in which two separate cork layers or sections 8 are applied to the cylinder 1 as distinguished from the single continuous layer 7 hereinbefore described. In this modified form there are also provided outside ring members 9 preferably formed of chamois. These chamois rings 9, which are soft and compressible are not intended as a substitute for the cork packing 7 and 8, but are merely for the purpose of wiping from the cylinder walls any grit or fine partlcles of foreign matter that might be carried into the cylinder with the asoline and thus prevent this grit from wor ing in between the said cork packing and cylinder walls. It is, of course,obvious that these chamois rings can also be used in the piston construction as shown in Figs. 2, 3 and 4.

In forming these chamois rin they are simply cut from a sheet of chamols in the fiat form as illustrated in Fig. 5, and thereafter forced over the ends of the piston, the inside diameter of the chamois ring 9 in its original form as shown in Fi 5, bemg less than the outside diameter of t e piston. In applying this chamois ring to the piston'the same is stretched over the ends of said piston and will be caused to assume the substantial fiat position as shown in Fig. 6.

As hereinbefore stated this piston may be constructed in many ways within th'scop loo lll

Lof the invention, the essential characteristics of the invention comprising a hollow cylindrical metal member of relatively thin metal, provided with a relatively thin sheet or laye of cork or similar composition. n

What I claim is: 1. The combination with a cylinder, of a piston freely mounted within said cylinder,

said piston comprising a cylindrical member,

disks closing the ends of said cylindrical member, said disks extending slightly beyond the outer circumference of the cylinder member to provide circumferential flanges, and a relatively thin layer of cork secured directly to the outer circumference of the cylindrical member and covering substantially the entire circumferential surface between said flanges.

2. rllhe combination with a cylinder, of a piston freely mounted within said cylinder, said piston comprising a cylindrical member, disks closing the ends of said cylindrical member, said disks extending slightly beyond the outer circumference of the cylinder member to provide circumferential flanges, the cylindrical member and disks bein made of relatively thin metal, and a relative y thin layer of composition cork secured directly to the outer circumference of the cylindrical member between said anges in sliding con tact with the cylinder walls, the width of said flanges being slightly less than the thickness of the cork layer. l

3. In a hollow piston,` the combination with `a relatively thin layer of cork applied to its engaging surface, of wiper rings also applied to the engaging surface of said pisy on, adjoining the outside edges of said cork ayer.

4. In a hollow piston, lthe combination -with a relatively thin` layer of cork applied toits engaging surface, of chamois wiper ringsV also applied to the engaging surface of said piston, adjoining the outside edges of said cork layer. 5. A substantiallyrigid non-compressible l closed hollow piston having a relatively thin layer of cork secureddirectly to its engaging surface.

. der and a layer of sheet cork applied directly to and covering substantially the entire circumferential face of said cylinder.

10. A hollow piston, comprising a cylinder, plates or discs closing the ends of said cylinder, the edges of said discs extending slightly beyond the outer circumference of said cylinder to provide circumferential flanges, and a relatively thin layer of sheet cork afpplied directly to the outer circumferential the cylinder between the flanges, the width ofsaid flanges bein slightly less than the thickness of the corr layer.

, 11. The combination with a cylinder, of a piston freely mounted I`within said cylinder, said piston' comprising a closed hollow metallic member and a layer of cork secured directly 'to and surrounding substantially the entire circumference of said piston in contact with the cylinder walls.

In testimony whereof I aiiix my signature.

ERNEST H. THOMPSON. l

6. A closedhollow piston having a rela I tively thin layer of cork cemented directly to its engaging surface.

7. A hollow piston, comprising a cylinder,

plates or discs closing/the ends of said cylinder and a layer of sheet cork adhesively applied directly to the outer circumferential face of said cylinder.

, 8. A hollow piston, comprising a cylinder, y plates or discs closing the ends of said cylinder and a layer of sheet cork applied directn '1y to the outer circumferential face of said cylinder and extending substantially to the ends of said cylinder.

9. A hollow piston, comprising a cylinder .having thin metallic' walls, thin metallic 

